I've got a Komatsu excavator I use frequently. It feels like the power it had when first acquired has waned since then. It's had oil changed, new fuel filter, new lift pump, new fuel lines, new air cleaners and hydraulic oil change all within the last year. But the power still just doesn't feel there like it used to. It's still usable but some things have become difficult to do with it. Could a turbo, like get dirty and lose compression? Maybe a leak in the inter-cooler or plumbing? Sheared vanes on the impellers? Could any of those cause a noticeable loss in power without some obvious kind of failure sign showing? Do turbo's even generally ever fail like that?

I will admit, when it comes to turbo's I really only know what I've read. I have to practical experience in diagnosing a possible turbo related problem. I may be looking in the wrong spot even. Maybe the hydraulic pump is just getting old and worn out. It just doesn't sound like the engine is revving as high as it did originally.

Thanks for any input. I got a part number for the turbo and the hydraulic pump. I'm going to see what I can find but I'd imagine the turbo will be a fraction of the cost of a hydraulic pump for a sizable excavator.

My experience is only with big trucks, but a leak in the charge air cooler can cause a gradual loss in power. They can be pressure tested. A turbo will fail quickly and often cause smoke in the exhaust.
An injector failure will cause rough running and sometimes make a metallic knocking noise, but can usually be diagnosed by aiming a laser thermometer at each exhaust port (at the manifold).

[This message has been edited by williegoat (edited 09-20-2018).]

quote Originally posted by Khw: Thanks for any input.

Are you sure you're not just trying to dig harder dirt?

I see the problem... it's not a Cat. 😂

If you have a boost gauge, compare the boost levels to the factory specs. If it's significantly low, you may have a boost leak.

Also, is it a direct injection engine? If so, take a peek in the intake manifold. DI engines have a habit of clogging the intake manifold with PCV gunk. Over time, it can restrict the intake enough to lose power.

As others have said, check for air leaks.

I've ran into the spring clamps that actually spread a bit when you "give it the beans", and you'd never know there was a leak otherwise.

quote Originally posted by MidEngineManiac: I see the problem... it's not a Cat. 😂

I love those yellow motors

I do not usually like their forklifts, but I got to drive a 22,000 lbs Cat lift with a 3208 a few times. That one, I liked.

Thanks you all for the replies. I will check to see if it's direct injection. I'll also see if I it has a boost gauge on it. Stupidest thing is the status cluster hasn't worked right since he bought it. It shows temp and fuel level just fine but I don't think any of the displays below that, or any of the indicator lights below that, work. When I'm switching between the various output selections I usually have to turn it off and restart it. Then count the beeps as I press the advance button until I've gone the needed number of beeps for the different outputs. Same with track speed. Hi, Me or Lo and no lights to show which you are currently in. I've been trying to get him to let me put a new cluster in it for years. Around $800 for the cluster though so...

Edit: Oh and I'm not a big fan of Cats.

[This message has been edited by Khw (edited 09-21-2018).]

On modern diesel engines with a common fuel rail you check the injector flow balance to diagnose faulty injectors. Also you take off the oil fill cap while running to see if there is excessive piston blow by. Just some quick and dirty tests to check the health of the engine.

Looks like I found the problem. The fuel injector pump ran off the crank pully has 2 belts on it. One of them has snapped and the other was loose in comparison. Tightened up that one and have 2 new belts on order. I am unsure if it is 100% of what it used to be but so far it’s much better than it was. Thanks all. Your suggestions got me looking at the injectors and the pump which made me notice the drive belts for them.

Edit: I just got back from breaking up some ground to scoop and screen, and the excavators power it tons better. Even running smoother and cooler again. Of course I need to fill up that 100 gallon tank on it again now. /sigh Gravity feed diesel tank is so boring to fill from.

[This message has been edited by Khw (edited 10-11-2018).]

That's good to hear. I'm glad it was a simple and inexpensive fix. Now, get back to work!

I know you found the issue - but Im curious if you could share the turbo PN. For reasons.